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binary_tree_max_level_sum.cc
59 lines (48 loc) · 1.52 KB
/
binary_tree_max_level_sum.cc
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/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int maxLevelSum(TreeNode* root) {
std::queue<TreeNode*> q;
int curr_level = 1, max_level = 1;
int curr_sum = 0, max_sum = root->val;
TreeNode *marker = nullptr;
q.push(root);
q.push(marker);
while (q.size() > 1) {
auto node = q.front();
q.pop();
if (node != marker) {
curr_sum += node->val;
if (node->left)
q.push(node->left);
if (node->right)
q.push(node->right);
} else {
// Go to next level
if (curr_sum > max_sum) {
max_sum = curr_sum;
max_level = curr_level;
}
curr_sum = 0;
curr_level++;
q.push(marker);
}
}
// Check last level
if (curr_sum > max_sum) {
max_sum = curr_sum;
max_level = curr_level;
}
return max_level;
}
};